The present invention relates to a method for prediction of the internal resistance of an energy storage battery in assumed environmental and battery state conditions. The present invention also relates to a monitoring device for energy storage batteries having measurement means for measurement of parameters for the environmental and battery state conditions for the energy storage battery and also having computation means. The present invention also relates to a product in the form of a computer program with program code means for carrying out the method mentioned above.
During operation of energy storage batteries, in particular starter batteries in motor vehicles, there is a need to determine the instantaneous state of the energy storage battery and to predict a future state in assumed environmental and battery state conditions. For example, it is desirable to determine the starting capability of a starter battery for starting an internal combustion engine in assumed temperature conditions. It is known for the instantaneous internal resistance to be determined for this purpose. This may be done, for example, from the drop in voltage on starting as the quotient of the voltage change divided by the current change. The internal resistance may also be obtained by matching the voltage and current information for the energy storage battery to a relatively complex equivalent circuit. An internal resistance determined in this way may then be used as a prognosis for a future starting process.
DE 198 47 648 A1 discloses a method for determination of the state of charge and of the high-current load capacity of batteries, in which the internal resistance of the battery is determined by means of a voltage and current measurement on high load, for example, during the starting process. Furthermore, the state of charge SOC of the energy storage battery is determined in a first state. This is done, for example, by measurement of the no-load voltage. The internal resistance is subdivided into a part which is only temperature-dependent and is virtually independent of the state of charge, and into a component which varies to a major extent with the state of charge for states of charge below 50%. A no-load voltage for a subsequent time is predicted from the internal resistance that has been subdivided in this way for a predetermined temperature and from the most recently determined state of charge, from which no-load voltage it is possible to use the known current required for starting an internal combustion engine to derive a statement about the capability of the energy storage battery for starting.
It would be advantageous to provide an improved method for predicting the internal resistance of an energy storage battery in assumed environmental and battery state conditions, by means of which, for example, the starting capability of a starter battery for a motor vehicle for a subsequent time can be predicted. It would be also advantageous to provide a monitoring device for energy storage batteries having measurement means for measurement of parameters for the environmental and operating state conditions for the energy storage battery, and having computation means which are designed to carry out the method described above. It would be also advantageous to provide a product in the form of an embodied computer program with program code means which are designed to carry out the method described above when the computer program is run using a processor device.
It would be advantageous to provide a system and/or method that includes any one or more of these or other advantageous features.